JP2009526183A - Sealed flange joint for high pressure and high purity gas channels - Google Patents

Abstract

A sealed flange joint for high pressure and / or high purity gas channels is provided.
A sealed flange joint for high pressure and / or high purity fluid channels comprises a first flange (10) having a first fluid channel (12) and a cylindrical front cavity (14). The front cavity (14) has an axial boundary defined by the polished surface (18) and a radial boundary defined by the peripheral surface (20). The first fluid channel (12) extends axially through the first flange (10) and opens into the polished surface (18). The polymer seal ring (30) has a radially outer surface (32) and a radially inner surface (34) that engages the peripheral surface (20) of the front cavity with the radially outer surface (32). Is mounted in a cylindrical front cavity (14). A second flange (16) is detachably fixed to the first flange (10), and the second flange has a second fluid channel (22) that is axially continuous with the first fluid channel (12). . This second flange (16) has an axially projecting cylindrical front nipple (24) with a conical head (26), and the second fluid channel (22) is of the conical head (26). There is an axial opening in the end surface (28). The conical head (26) engages the radially inner surface (34) of the seal ring (30) and attaches the seal ring having the radially outer surface (32) to the peripheral surface (20) of the front cavity (14). Press in the radial direction.
[Selection] Figure 3

Description

  The present invention relates generally to sealed flange joints for fluid channels, particularly for high pressure and / or high purity gas channels.

  The increased use of specialty gases and the increased level of purity required in today's industry has created a need for the highest quality and integrity, increasingly complex and sophisticated delivery systems. .

  For example, in the semiconductor / chip manufacturing industry, high quality gas channels are required. The reason for this is that impurities in the gas can adversely affect the electrical characteristics of the device and significantly reduce the manufacturing yield. These gases are often very reactive, corrosive and / or toxic.

  Therefore, specially adapted equipment and high quality equipment are required to contain, handle and deliver ultrapure gas. In such systems, the quality of the joints and seal members is particularly important in preventing gas leaks or air ingress into the system. Since high quality seals must withstand pressures above 200 bar, it is more important and difficult to obtain high quality seals.

  Due to these stringent requirements for purity and high operating pressure, seal systems for ultra high purity systems are often custom manufactured. In this connection, it is known to use a metal O-ring or a flat metal gasket at the junction between the delivery pipe and the valve outlet port of the gas cylinder. However, if the metal O-rings withstand high pressures, they leave a recess in the sealing surface that they contact, which makes the O-ring unfit for use with non-removable connections.

  Unfortunately, there is a strong need for removable connections for high purity applications. The reason is that the detachable connection allows the replacement of equipment and the replacement of damaged or defective parts.

  Accordingly, there is a need for a sealing technique that is compatible with high purity, high pressure gas channels and suitable for detachable connections.

  In order to satisfy these conditions, the present invention proposes an improved sealed flange joint as claimed in claim 1.

  The sealed flange joint for a fluid channel in the present invention comprises a first flange having a first fluid channel and a cylindrical front cavity. The front cavity has an axial boundary defined by the polished surface and a radial boundary defined by the peripheral surface. The first fluid channel extends axially through the first flange and opens into the surface of the polished front cavity. The polymer seal ring has a radially outer surface and a radially inner surface that is mounted within the cylindrical front cavity such that the radially outer surface engages the peripheral surface of the front cavity. The flange joint further includes a second flange, and the first flange and the second flange are detachably fixed to each other. The second fluid channel passes through the second flange continuously in the axial direction with the first fluid channel. The second flange has a second fluid channel that is axially continuous with the first fluid channel. The second flange has an axially projecting cylindrical front nipple with a conical head, and the second fluid channel opens axially into the end surface of the conical head. It should be noted that the conical head engages the radially inner surface of the polymer seal ring and radially presses the seal ring having the radially outer surface against the peripheral surface of the front cavity.

  Therefore, the present invention proposes a joint structure in which the nipple that presses the inside of the polymer seal ring strongly compresses the polymer seal ring in the radial direction. This is due to the structure of the nipple and the polymer seal ring when both flanges are assembled and fixed together. A nipple with a conical head converts axial pressure into radial compression of the polymer seal ring. Therefore, this seal ring is radially compressed and actually confined between the nipple and the front cavity surface, which results in a high quality seal adapted to high operating pressures, as is often the case in high purity gas applications. Can provide.

  In addition to the improved sealing function, the joint has proven advantageous in many ways. First of all, the polymer seal ring does not damage the surface in contact with the ring and is therefore more suitable for reconnecting and removing joints than a metal flat gasket or O-ring. Secondly, the use of a flange joint enables assembly of the joint in the axial direction. For example, two screws can be fastened together by screws, so that no torsional force is generated during assembly. This also solves the problem of friction in the seal area which can generate undesirable metal particles.

  Furthermore, the structure allows the polymer seal ring to begin to deform (or force) during assembly and allows the polymer seal ring to be placed in place within the front cavity. This is mainly achieved by the conical head of the nipple which applies a radial force and thus reduces the (axial) assembly force.

  Also, the nipple (at least its conical head) rests on the radially inner surface of the seal ring, thus isolating the seal ring from the fluid channel and thus protecting the seal ring from contacting the fluid directly. . The influence of the protective structure of the seal ring is observed especially by the improved behavior during thermal insulation chock evaluation.

  The sealed flange joint according to the present invention can be advantageously used to make connections between various types of equipment where a high quality sealing function is required. This flange joint has applications in various business areas such as aerospace, mechanical engineering, fixed hydraulic technology, chemical industry, process engineering, semiconductor / chip manufacturing, medical engineering. The joint of the present invention does not necessarily include two different flanges, and one flange may be integrated with a predetermined part of the device (in this case, corresponding to a fitting flange).

  The peripheral surface of the front cavity preferably has a central bulge that engages the radially outer surface of the polymer seal ring. As a result of the convex shape of the peripheral surface in this way, the compressive force at the center of the seal ring becomes higher (pressure becomes higher), and thus the sealing function can be strengthened. Further, the bulge can lock the polymer seal ring in the front cavity while the joint is removed.

  In assembling the two flanges, the first flange and nipple delimit the seal ring chamber within the cylindrical front cavity. The compressed seal ring preferably has substantially the same cross-sectional shape as the seal ring chamber. Therefore, in the uncompressed state, the cross section of the seal ring is 1.03 to 1.10 times, preferably 1.03 to 1.07 times, the cross section of the seal ring chamber.

  The first flange preferably comprises a first axial abutment surface surrounding the cylindrical front cavity, while the second flange comprises a second axial abutment surface surrounding the nipple. When assembling the flange, the first contact surface and the second contact surface are pressed against each other in the axial direction. These abutment surface contacts limit axial displacement of the flanges that are close to each other, thus preventing the polymer seal ring from crashing. It also protects the sealing area (seal ring, nipple, seal ring chamber) from axial chocks.

  In one embodiment, the first flange further comprises a ring-shaped groove provided in the first axial abutment surface, the ring-shaped groove surrounding the cylindrical front cavity and having an inner radial surface and an outer radial direction. A radial boundary is defined by the surface. A second seal ring is disposed in the ring-shaped groove, the second seal ring engages the outer radial surface, is radially spaced from the inner radial surface, and is outside the inner ring surface in the ring-shaped groove. Is sealed in the radial direction. To check for leaks, the connection channel connects the ring channel to a leak test port in the first flange.

  This second seal ring, the elastomeric O-ring, seals the inner ring channel at the joint between the abutting surfaces, which prevents air ingress and manages the seal quality of the main seal ring. Furthermore, moisture and other impurities can be prevented from reaching close to the main polymer seal ring.

  To facilitate assembly of the flange joint, the first flange can include an axially projecting positioning head that forms a first axial abutment surface, and the second flange is a second axial abutment. A positioning cavity may be provided that forms a surface, the positioning cavity receiving an axially projecting positioning head and positioning it radially. This structure not only helps the positioning of the two flanges, but the positioning of the head / cavity structure allows it to withstand radial forces at the joint.

  Another advantage of the positioning cavity is that the nipple can be protected when the first flange is not assembled to the second flange. Thus, the nipple has a height that is less than or equal to the depth of the positioning cavity. If desired, the cavity, and thus the nipple, may be covered by a removable cover.

  In some embodiments, the nipple height is such that when the first abutment surface and the second abutment surface are axially pressed together, a small gap causes the end surface of the conical head of the nipple to pass through the front cavity. It can be defined to separate from the polished surface. In such a case, it is preferred that the polymer seal ring is designed to enter and fill this small gap in the compressed state. In this way, the formation of dead volume around the fluid channel where particles, condensate or gas / fluid may be deposited can be prevented.

  More particularly, with respect to the main polymer seal ring, it is preferred to produce the polymer seal ring from a thermoplastic polymer that has low gas permeability and low creep under load (ie, high pressure). Of course, the selected polymer should not be filled with hard particles (eg, glass, etc.) to prevent damage to the seal surface. A preferred polymer that meets these criteria is polychlorotrifluoroethylene (PCTFE), which can be used for operating temperatures in the range of −60 ° C. to 100 ° C., and polyimide or PFA as other materials that can be used for the primary seal ring There is.

  To prevent errors during assembly and alignment, the flange joint can include a pin indexing system as is known in the art.

  According to another feature of the invention, a sealed flange joint seal ring as described above has a radially inner surface and a radially outer surface, the radially outer surface comprising a hollow central cylindrical surface. The radially inner surface comprises a central frustoconical surface.

  In a preferred embodiment, the radially inner surface further includes a first cylindrical surface up to the end where the diameter of the central frustoconical surface is maximum and the diameter of the central frustoconical surface is minimum. And a second cylindrical surface up to the end. Preferably, in the uncompressed state, the width of the seal ring in the region of the first cylindrical surface is about 1.4 to 2.2 times the width of the seal ring in the region of the second cylindrical surface. It has become.

  The seal ring can have flat annular upper and lower surfaces. Annular upper and lower surfaces with flat chamfered corners can be joined to a hollow central cylindrical surface.

  The present invention will now be described by way of example with reference to the accompanying drawings.

  The figure shows a preferred embodiment of a sealed flange joint according to the present invention. This sealed flange joint requires a pair of flange assemblies in a sealed state, as will become apparent later. Such flange joint structures are used for example in the fluid, especially gas, various sealed connections of channels and in-fluid / gas confinement, handling or metering dispensing systems between the valve port of the gas cylinder and the delivery pipe it can. This type of flange joint is ultra-pure, extremely corrosive and is particularly suitable for applications using high pressure gases.

  Referring now to FIG. 3, there is shown a first flange 10 having a first gas channel 12 and a cylindrical front cavity 14. The first flange 10 can be provided at the end of the delivery pipe 15, for example. Reference numeral 16 generally indicates a second flange, and the two flanges 10 and 16 are detachably secured to each other as will be further described below. Such a second flange structure can be provided, for example, in a metering dispensing port of a gas cylinder valve. As can be appreciated, this second flange 16 can also be viewed as a mating flange because it is built into the valve port and not created as a separate flange.

  The front cavity 14 of the first flange 10 is defined by an axially polished surface 18 and a radial boundary is defined by a peripheral surface 20. The first gas channel 12 extends axially through the first flange 10 and opens into the polished surface 18 of the front cavity 14.

  The second flange 16 has a second gas channel 22 that passes through the second flange 16 that is continuous in the axial direction of the first gas channel 12. The second flange 16 further comprises an axially projecting cylindrical front nipple 24 having a conical head 26. The second gas channel 22 opens axially into the end surface 28 at the tip of the conical head 26 (FIG. 5).

  The cylindrical front cavity 14 is fitted with a polymer seal 30 having a radially outer surface 32 and a radially inner surface 34 so that the radially outer surface 32 engages the peripheral surface 20 of the front cavity 14. It should be noted that. Further, the conical head 26 of the second flange 16 engages the radially inner surface 34 of the polymer seal ring 30 and radially presses the seal ring 30 along with the radially outer surface 32 against the peripheral surface 20 of the front cavity 14. is doing.

  As can be understood from the drawing, the assembly of the flanges 10 and 16 is performed by pressing these flanges in the axial direction (the shaft 33) so as to become one. The flanges are preferably fastened together with screws 35 that maintain the flanges in contact with each other. In this embodiment, four screws 35 are inserted from the exposed surface of the first flange (FIG. 1), and the threaded portions of these screws are in corresponding threaded bores in the second flange 16. They are engaged (see FIG. 4).

  As the flanges 10 and 16 are assembled, the nipple 24 is positioned in the front cavity 14. A nipple 24 having a conical head 26 converts axial pressure into a radial compressive force of the seal ring 30. Thus, the seal ring 30 is radially compressed and confined between the nipple 24 and the peripheral surface 20 of the front cavity 14, thereby providing a high quality seal adapted to high working fluid or gas pressure.

  As can be seen from FIGS. 5 and 6, the peripheral surface 20 of the front cavity 14 preferably has a central bulge 36 that engages the radially outer surface 32 of the polymer sealing single 30. As a result of such a convex shape of the peripheral surface 20, the compressive force (pressure) at the center of the seal ring 30 becomes higher, so that the sealing performance of the joint can be improved. The bulge portion 36 can also hold the seal ring 30 in the front cavity 14 when the flanges 10 and 16 are separated from each other.

  In this embodiment, the first flange 10 preferably comprises a first axial abutment surface 38 that surrounds the cylindrical front cavity 14, and the second flange 16 preferably comprises a second axial abutment surface 40 that surrounds the nipple 24. . These abutment surfaces 38 and 40 abut when the flanges 10 and 16 are assembled to withstand the axial pressure resulting from fastening the flanges. In fact, these abutment surfaces 38 and 40 prevent over-compression of the seal ring 30 during assembly and more generally protect the sealing function from axial chocks. As a sealing function and further protection of the joint, the screw 35 withstands and prevents torsional forces applied to the joint.

  As can be seen from the various figures, the first flange 10 and the nipple 24 delimit a chamber 42 (shown only in FIG. 6) of the seal ring within the cylindrical front cavity 14. In the assembled state, which also means the compressed state of the polymer seal ring 30 (i.e. where the abutment surfaces are in contact with each other), the polymer seal ring is preferably a seal ring chamber 42 (completely filled by this seal ring 30). 6) and substantially the same cross section (as shown in FIG. 6).

  In this regard, the end surface 28 of the conical head 24 of the nipple and the polished surface 18 of the front cavity 14 when the first and second abutment surfaces are axially pressed together. It can be further understood that a small gap g remains in between. In this embodiment, the seal ring 30 enters the small gap g in the radial direction and fills this gap. Even a small gap g between the seal ring chamber 42 and nipple tip 28 and the polished surface 18 is filled by the seal ring 30, so that dead volume such that gas / fluid, condensate or particles can accumulate. Part does not occur in this area.

  In FIG. 6, such a special structure of the polymer seal ring 30 that completely fills the chamber 42 and the gap g can be observed well. In contrast, in FIG. 5 where the assembly is not complete (the abutment surface is not in contact), the seal ring 30 does not fill the gap g separating the nipple tip 28 and the polished surface 18. Observe.

  This embodiment provides a special effective sealing function that surrounds the gas / fluid channels 12 and 22 at the interface between the two flanges 10 and 16. As can be clearly seen from FIG. 6, a seal ring 30 is confined within the seal ring chamber between the nipple 24 and the walls (18, 20) of the front cavity. The intimate contact between the abutment surfaces 38 and 40 closes the seal ring chamber 42 and thus prevents creeping of the seal ring at (or through) the joint. Since only the opening in the seal ring chamber 42 has a very narrow gap g, only a very small portion of the seal ring 30 is directly exposed to the gas pressure in the channel. Due to this construction, especially when the seal ring chamber 42 is closed by the abutment surfaces 38 and 40, the high pressure gas flowing in the gas channels 12 and 22 will not move the seal ring 30.

  However, in connection with the above structure, in the assembled state, it is possible to design the seal ring 30 so that the seal ring 30 does not protrude in the gas channels 12, 22 and not only fills the chamber 42 but also fills the gap g. It will be understood that it is preferable. As can be seen from FIG. 6, the seal ring 30 in the gap g is flush with the surface of the channel 12 in the first flange 10.

  In summary, the proposed structure featuring a nipple 24 having a conical head 26 causes radial compression of the seal ring 30 when the flanges 10 and 16 are assembled. As a result, since the traction force of the seal ring 30 is mainly in the radial direction, the axial collective action force is reduced, and the deformation of the radial seal ring starts to push the seal ring into the seal ring chamber 42. it can. In the final assembled structure (as shown in FIG. 6), the seal ring 30 is confined within the seal ring chamber 42 and is basically compressed into the seal ring chamber over the entire circumference (excluding the gap g). .

  In the present embodiment, the first flange 10 includes a ring-shaped groove 44 in the first axial contact surface 38. The ring-shaped axial groove 44 surrounds the cylindrical front cavity 14 and is delimited radially by an inner radial surface 46 and an outer radial surface 48. A second seal ring 50, which is preferably manufactured from an elastomer material, is disposed in the ring-shaped groove. The second seal ring 50 engages the outer radial surface 48, is radially spaced from the inner radial surface 46, and seals toward the outside of the inner ring channel 52 in the ring-shaped groove 44. The connection channel 54 connects the ring channel 52 to a leak test port 56 in the first flange 10. This leak test port can be closed by a plug 58.

  The second seal ring 50 seals the inner ring channel 52 at the joint between the abutment surfaces, thereby preventing air ingress and the quality of the seal of the main seal ring 30 via the connection channel 54 and the port 56. Can be managed. This further prevents moisture (and impurities) from reaching close to the main seal ring 30.

  To ensure a seal against atmospheric pressure and moisture, the plug 58 is preferably a screw (eg, an M4 screw) that is screwed into a corresponding thread in the port 56. Reference numeral 59 indicates a seal ring, for example, a PTFE seal ring, disposed below the head of the screw 58.

  The assembly of the two flanges 10 and 16 is facilitated by the design of this embodiment. In FIG. 3, it can be appreciated that the first flange 10 includes an axially projecting positioning head that forms a first axial abutment surface 38. The second flange 16 comprises a positioning cavity that in turn forms a second axial abutment surface 40, so that the positioning cavity receives a positioning head projecting in the axial direction and positions it in the radial direction. Yes. Such a construction ensures that the elements with different main sealing functions are correctly positioned. Furthermore, the axially extending mating surfaces 57 and 57 'of the head and cavity each withstand radial chocks and thus protect the sealing function.

  The nipple 24 preferably has a height that is less than or equal to the depth of the positioning cavity. Thus, the nipple is protected by the peripheral cavity when the first flange 10 is not connected to the second flange. Furthermore, the inside of the cavity can be protected by a cover (not shown).

  As is conventionally done in the art, the joint can include a pin indexing system. This is illustrated in FIG. 2, in which reference numeral 60 indicates the first index pin and reference numeral 60 'indicates the second index pin, but only one pin is required to perform the coding function. Is enough. A pin 60 is fixed (screwed) to the first flange 10, and this pin is engaged in a corresponding hole 61 in the second flange 16. The indexing pins (extending in the axial direction) not only work for coding purposes, but also withstand the rotational forces at the joints.

  In this embodiment, the polymer seal ring 30 has a specific shape adapted to the shape of the seal ring chamber 42 in the uncompressed state. In general, the cross-section (as shown in FIGS. 5 and 6) of the seal ring 30 before use (before compression) can be 3-10% larger than the cross-section in the compressed state.

  As can be seen from FIG. 5, the radially outer surface 32 includes a central hollow cylindrical surface 62. The radially inner surface 34 includes a central frustoconical surface 64, a first cylindrical surface 66 to the end of the diameter of the central frustoconical surface 64, and a central frustoconical. And a second cylindrical surface 68 up to the end with the smallest diameter of the shaped surface. In the uncompressed state, the width of the seal ring 30 in the region of the first cylindrical surface 66 is approximately 1.4 to 2.2 times the width of the seal ring 30 in the region of the second cylindrical surface 68. Yes. More important in designing the first cylindrical surface 66 is that, in the compressed state, this first cylindrical surface should preferably not protrude into the gas channel, as already mentioned above.

  Further, when viewed from the axial direction 33, the seal ring 30 has a flat annular upper surface 70 and a flat annular lower surface 72. Chamfered corners 74, 74 ′ join the annular upper surface 70 and lower surface 72 to the central hollow cylindrical surface 64.

  The surface of the seal ring 30 and all these structural features of the seal ring chamber 42 contribute to improved shape matching, which causes the chamber 42 to be completely tightly sealed by the polymer seal ring 30. The polymer seal ring 30 is maintained at a constant pressure around it by the walls of the chamber 42 (excluding the gap g) due to compression (reduction in volume).

  In summary, in this sealed flange joint, the seal ring 30 is actually compressed over its entire circumference by confinement in the seal ring chamber 42 (except for the gap g). During assembly of the flanges 10, 16, the seal ring 30 is first pushed radially and compressed by the conical head 26 of the nipple 24. When assembled, the seal ring is enclosed within a seal ring chamber 42 (whose cross-section is smaller than the cross-section of the uncompressed seal ring 30), so that the walls of the seal ring chamber apply pressure almost entirely around the seal ring. . As a result, peripheral pressure is applied to the seal ring, and a high-quality seal can be provided. Furthermore, the quality of the seal is improved by increasing the radial compression of the seal ring 30 between the nipple 24 and the bulge portion 36. The generation of a radial compression force through the nipple cone head 26 can reduce the required assembly force in the axial direction.

  In other words, this design reduces assembly force and moves the seal ring 30 into place, confines the seal ring within the seal ring chamber 42 and presses the seal ring to match the seal ring chamber 42. Within this seal ring chamber, the seal ring 30 is compressed at the periphery, except for the gap g (as already described for its shape). Therefore, almost the entire surface of the seal ring 30 is involved in the seal. Such a structure is quite different from a conventional sealing structure in which the O-ring is compressed (typically in the assembly axial direction), for example in two opposing peripheral parts.

  It should also be noted in this example that the polymer material must have low gas permeability and low creep, especially at high pressures. Since such materials are generally not elastomers, but less rigid, more rigid polymers, seal rings generally undergo plastic deformation during assembly.

  A suitable material for the polymer seal ring 30 is, for example, polychlorotrifluoroethylene (PCTFE). This material has low gas permeability and low creep when subjected to a load. This material also allows the operation of valves between 60 ° C and 100 ° C.

  However, one elastomer ring may be used in applications with less stringent sealing conditions, for example at lower pressures, especially with liquids.

  With regard to the secondary sealing function, the O-ring 50 can be made from an elastomeric polymer, such as NBR (nitrile butadiene rubber) or Viton® (DuPont fluoroelastomer).

  As already mentioned, the joint structure can be applied to provide a removable sealed connection between various gas / fluid devices. A distinctive application is in the field of high purity gas cylinders, which so far have included valves with special couplings for connection to gas lines and the like. Such bulk couplings incorporated into the bulk of the valve body are extremely fragile and are often damaged by mechanical shock. This means that the entire valve has to be replaced in the gas cylinder, which means that due to high purity applications, the maintenance and cleaning work of the gas cylinder is a significant burden.

  This flange joint provides a sealing solution that eliminates maintenance and cleaning problems when the coupling is damaged. For example, the valve opening of the gas cylinder valve can be designed as the second flange 16, and then the structure of the first flange 10 can be provided at one end of the sleeve member, while the other end can be designed to have a specific coupling structure. . The sleeve member is mounted such that its first flange end is located in a valve structure having a second flange structure, thus providing the gas cylinder valve with the specific coupling desired. If this particular coupling breaks, it is only necessary to replace the sleeve member with a new sleeve member. This replacement can be easily and effectively performed by the present joint structure. Since it is no longer necessary to replace the entire gas cylinder valve, troublesome maintenance and cleaning operations are unnecessary.

  It will be appreciated that the robustness of the flange structure allows it to be reconnected and removed at least 50 times without compromising the quality of the seal (of course, this seal ring must be replaced before reconnection). May be good).

It is a front view of the preferable Example of the flange joint concerning this invention seen from the outer side of the 1st flange. It is sectional drawing along CC line in FIG. It is sectional drawing along the BB line in FIG. It is sectional drawing along the AA line in FIG. FIG. 5 is a detailed view of a region D in FIG. 4 showing the polymer seal ring in a state before compression. FIG. 5 is a detailed view of a region D in FIG. 4 showing the polymer seal ring in a state after compression.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 1st flange 12 1st fluid channel 14 Cylindrical front cavity 15 Delivery pipe 16 2nd flange 18 Polished surface 20 Peripheral surface 22 2nd fluid channel 24 Cylindrical front nipple 26 Conical head 28 End surface 30 Polymer seal Ring 32 radially outer surface 34 radially inner surface 35 screw 38 first axial contact surface 40 second axial contact surface 42 sealing chamber 44 ring groove

Claims (17)

A first flange (10) having a first fluid channel (12) and a cylindrical front cavity (14), the front cavity (14) being axially bounded by a polished surface (18). And a radial boundary is defined by a peripheral surface (20), the first fluid channel (12) passes axially through the first flange (10) and the polishing of the front cavity (14) Open in the surface (18) formed,
The cylindrical front cavity has a radially outer surface (32) and a radially inner surface (34) such that the radially outer surface (32) engages the peripheral surface (20) of the front cavity. A polymer seal ring (30) fitted to (14);
An axially projecting cylindrical shape with a second fluid channel (22) passing through the second flange (16) and a conical head (26) so as to be axially continuous with the first fluid channel (12). A second flange (16) having a front nipple (24), the second fluid channel (22) opening axially into an end surface (28) of the conical head (26), The first flange (10) and the second flange (16) are detachably fixed to each other,
The conical head (26) engages the radially inner surface (34) of the polymer seal ring (30), the radially outer surface (32) of the seal ring being the said of the front cavity (14). A sealed flange joint for a fluid channel adapted to radially press the seal ring into contact with the peripheral surface (20).   The peripheral surface (20) of the front cavity (14) has a central bulge (36) that engages the radially outer surface (32) of the polymer seal ring (30). Sealed flange joint.   The first flange (10) and the nipple (24) constitute a seal ring chamber (42) in the cylindrical front cavity (24), and the compressed seal ring (30) is the seal A sealed flange joint according to claim 1 or 2, having substantially the same cross-sectional shape as the ring chamber (42).   In a non-compressed state, the cross section of the seal ring (30) is 1.03 to 1.10 times, preferably 1.03 to 1.07 times the cross section of the seal ring chamber (42). 4. A sealed flange joint according to claim 3, wherein: The first flange (10) comprises a first axial abutment surface (38) surrounding the cylindrical front cavity (14),
The second flange (16) comprises a second axial abutment surface (40) surrounding the nipple (24),
A sealed flange according to any one of the preceding claims, wherein the first abutment surface (38) and the second abutment surface (40) are pressed axially with respect to each other. Joint.   When the first abutment surface (38) and the second abutment surface (40) are pressed against each other in the axial direction, a small gap (g) forms the conical head (26) of the nipple (24). 6. The sealed flange joint of claim 5, wherein the end surface (28) of the front cavity (14) is separated from the polished surface (18).   The sealed flange joint according to claim 6, wherein when compressed, the seal ring (30) enters the small gap (g) radially and fills the gap. . The first flange (10) further includes
A ring-shaped groove (44) provided in the first axial contact surface (38), the ring-shaped groove (44) surrounding the cylindrical front cavity (14) and having an inner radial surface; A radial boundary is defined by (46) and the outer radial surface (48);
A second seal ring (50) provided in the ring groove (44) is further provided, the second seal ring (50) engaging the outer radial surface (48) and the inner diameter. Radially spaced from the directional surface (46) to radially seal the inner ring channel (52) in the ring groove (44) to the outside,
A connection channel (54) connecting the inner ring channel (52) to a leak test port (56) in the first flange (10) according to any one of claims 4-7. Sealed flange joint. The first flange (10) comprises an axially projecting positioning head that forms the first axial abutment surface (38);
The second flange (16) comprises a positioning cavity forming the second axially projecting (40), the positioning cavity receiving a positioning head projecting in the axial direction and positioning it radially. 9. A sealed flange joint according to any one of claims 5 to 8, which is adapted.   The sealed flange joint according to claim 9, wherein the nipple (24) has a height less than or equal to the depth of the positioning cavity.   The said 1st flange (10) and the said 2nd flange (16) are sealed by any one of Claims 1-10 currently pressed by the screw (35) in the axial direction. Flange joint.   The sealed flange joint according to any one of the preceding claims, further comprising a pin indexing system (60, 60 ').   13. A sealed flange joint according to any one of the preceding claims, wherein the fluid channel is a high pressure and / or high purity gas channel. Having a radially inner surface (34) and a radially outer surface (32);
Said radially outer surface (32) comprises a hollow central cylindrical surface (64);
A seal ring for a sealed flange joint according to any one of the preceding claims, wherein the radially inner surface (34) comprises a central frustoconical surface (64). The radially inner surface (34) further includes
A first cylindrical surface (66) to the end where the diameter of said central frustoconical surface (64) is maximum;
A second cylindrical surface (68) to the end where the diameter of said central frustoconical surface (64) is minimal;
In the uncompressed state, the width of the seal ring in the region of the first cylindrical surface (66) is about 1.4 to about the width of the seal ring in the region of the second cylindrical surface (68). The seal ring according to claim 14, wherein the seal ring is 2.2 times.   16. A seal ring according to claim 14 or 15, comprising a flat annular upper surface (70) and a flat annular lower surface (72).   The chamfered corner (74, 74 ') joining the flat annular upper surface (70) and the flat annular lower surface (72) to the hollow central cylindrical surface (64). Seal ring.

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